Pavement joint



' PAVEMENT JOINT Filed May 8, 1940 i 2 Sheets-Sfieet l INVENTOR.

R. B. TUFTS 2,311,286

Patented Feb. 16, 1943 UNITED STATES Pram OFFICE Robert B. Tufts,Atlanta, Ga.

Application May 8, 1940, Serial No. 334,046

1 Claim. (Cl. 94-17) The invention relates to joints for pavements andhas as an object the provision of a joint which will obviate irregularcracks in: pavements, particularly such as occur longitudinally of thecenter of the pavement.

It is an object of the invention to provide a joint of the characterthat will provide a division between portions of the pavement and whichwill be straight where it intersects the surface. 7

Further objects of the invention are to provide a joint of thischaracter that will provide for the support of the slab upon each sideof the joint by the slab on the other side; and that will allow of freeslight movements of the slabs relative to each other which are caused bywarping or expansion or contraction of the slabs.

Further objects of the invention will appear from the followingdescription when read in connection with the accompanying drawingsshowing illustrative embodiments of the invention, and wherein: I

Figure l is a perspective view of a portion of the metallic separatorfor a joint of the invention;

Fig. 2 is a plan view of the structure of Figure 1;

Fig. 3 is a side elevation;

Figs. 4 and 5 are transverse sections on the corresponding section linesof Fig. 3;

Fig. 6 is a perspective view of a slab cast with the metal providedbythe invention in situ and swung apart to show the form of the meetingsides;

Fig. 7 is a detail sectional view showing the result of movement ofwarpage of the slabs at the joint;

Fig. 8 shows a joint provided with material to provide for expansion;and

Fig. 9 shows modifications of the joint.

As shown the device comprises a sheet of metal having a verticallongitudinal portion l5 at its upper edge and a marginal flange H5 atits lower edge. Interspersed between portions l'l lying in the centralplane of the sheet and in a plane of the portion l5, there are shownportions struck out from the material of the plate of prismatic form,one portion H3 at the left of Figure 1 projecting in one direction fromthe sheet and the remaining portion l9 below the portion l8 projectingfrom the opposite surface of the sheet.

At 20 is shown a member similar to 18 but projecting in the oppositedirection therefrom,

and at 2! an oppositely directed portion similar to I9.

It will be seen that at each location of the oppositely projectingprismatic portions there is a shelf 22 provided which is horizontal andat which concrete cast against the form will overlap in such a mannerthat at alternate sections each slab will provide a support for theother slab upon opposite sides of the form.

At the junction 23 or in any of the flat places I! of the plates, therespective members may be perforated and dowel pins 24 may be passedthrough the openings. shown as perforated at 25, which perforations maybe utilized in the staking down of the form to hold the same in anupright position while the concrete is poured upon opposite sides, itbeing understood that the metal of the invention remains in situ afterthe pavement is cast.

The result of the embedding of the metal of Figures 1 to 3 inclusive inconcrete is indicated in cross section in Figures 4 and 5 wherein slab Asupports slab B at the section line 44, whereas the reverse is thecaseat section line 55.

The metal form of the invention may be coated upon either or both sideswith a substantial layer of asphalt, or other compressible material 40,Figs. 4, 5 and 7, and 28, Fig. 8, in which event the joint of theinvention will function as an expansion joint.

Fig. '7 illustrates the result when the two adjacent slabs have becomewarped or concave due to unequal temperatures of the upper and lowersurfaces, the joint having risen from the supporting ground anddeflection having taken place in the joint, the upper part of the jointhaving opened and the lower part of the joint having squeezed theasphalt coatings 40, and rotation having taken place about center 27.

In case the adjacent slabs should have warped to convex upper surfacesthe joint will open at the bottom and close at the top.

The yielding asphalt coating will give similar results as if the slabswere separated a small amount before warping takes place.

The yielding asphalt coatings further permit of longitudinal expansionof the slab units, limited by the thickness of the coatings and thejoint will open when contraction takes place.

Another form of the device is shown in Figure 9, wherein the metal ispushed out from the plane of the sheet in one direction only at eachsection, thereby providing that the upper portion 29 at each section hasa perpendicular face The bottom flange It is down to the shelves 30 and3|. This will provide greater strength for the support of each slab bythe other as the extent of the concrete which must shear in order tocause relative vertical movement between the slabs is greater than thatprovided by the first form of the invention referred to.

Joints of this character are quite suitable for a longitudinal joint atthe center of a roadway or for joints transverse to the roadway, ifspaced comparatively close to each other, and the metal form onlyrequires a simple rolling or stamping operation for production thereof.

Minor changes may be made in the physical embodiments of the inventionwithin the scope of the appended claim without departing from the spiritthereof.

I claim:

A joint for meeting edges of concrete slabscomprising a series of pairsof projecting ledges;

each pair comprising a ledge. projecting from the lower portion of theedge of one slab and a similar ledge projecting from the upper portionof the edge of the meeting slab; each of said meeting edges formed withcomplemental cavities to receive the opposing ledge; the lower and upperledges of adjacent pairs projecting in opposite directions at saidmeeting edges; opposed faces of the ledges of the pairs lying adjacent acommon horizontal plane whereby one ledger of .each pair of forms asupport for the other thereof; a face. of each ledge inclined to avertical plane through the joint passing through the center of thehorizontal faces of the ledges and merging into said vertical plane 2 toprovide straight line joints at the top and bottom of. the pavement; anda coating of compressible material carried by at least one of themeeting edges and covering the faces of the ledges including thehorizontal faces thereof.

ROBERT B. TU F'IS.

